IUPAC name of [Pt (NH3)2Cl(NO2)] is :
1) Cations are named first and anions(counter ions) are named later. In this case, there are no anions.
2) The ligands are named in alphabetical order and their prefixes carry no significance. Anionic ligands have a suffix –o attached in the end. So, ammine comes first followed by chloride and then nitrito-N. Since, NO2 is an ambidentate ligand. The letter N shows that the Nitrogen end of NO2 is bonded to the central metal atom and not the oxygen end.
3) This is followed by the name of the central metal and its oxidation state which is platinum(II)
So, the IUPAC name for Diamminechloridonitrito-N-platinum (II)